Test #2 of Pepsin as capping agent
From an earlier made batch of 500 ppm (125 mg) colloidal silver reduced and stabilized with Tannic Acid, I took 20 ml (5 mg) of it and placed it into a 250 ml E-flask with constant stirring and heating. Then added 100 mg Pepsin (so it's 100 mg Pepsin for 5 mg Silver) and let it stir and heat til it started to reach boiling temp.
I removed the flask, and placed it on a magnetic stirrer without heating, and let it continue to stir for 10 minutes to make sure that the capping process was completed.
After the 10 mins, I took 50 ml of my previously made bottle of simulated gastric fluid and poured it into another 250 ml E-flask, which I placed ion the heated magnetic stirrer and heated it til it reached 37 C, then removed it from the heated stirrer and placed it on my non-heated stirrer and added 20 ml of the above diluted 20 ppm tannic acid colloidal silver. Instantly remopved the flask and placed it so I could take this picture...
http://oi59.tinypic.com/3027zty.jpgMy comments: No change in color that confirms that the colloidal silver oxidizes to ionic form as silver chloride; no change in color or turbidity.
Then moved it back to the non-heated magnetic stirrer and let it continue to stir for 10 minutes, then removed it fromt he stirrer and took this 2nd picture...
http://oi62.tinypic.com/b48akl.jpgMy comments: The solution look the same as the previous one, confirming that time doesn't matter, as the capping agent still stands the gastric fluid.
I will keep the flask for some hours to see if there's any change in color and turbidity.
So, once a confirmation that Pectin indeed is a good capping agent. This time I used 100 mg Pectin for 5 mg Silver. So when doing 1000 ml pf 20 ppm (20 mg) Pectin capped colloidal silver, then 4 times as much Pectin can be used, i.e. 400 mg (0.4 gram). And this is probably too much anyway.